Method of bending and apparatus therefor



JNVENToR Filed April 4, 195o J F LAWSON METHOD OF BENDING AND APPARATUSTHEREFOR Nov. 28, 1933.

Patented Ney'. 2S,

. fvwm@ elm, Flfc ,A YFT* W UN Si ill/ PATENT il O it 3338565 FETHE) @FAND APPARATUS Jenn it". Lawson, Ereohlyn, N. Y., assigner te Steel andTubes, Ene., a eerporatien ci? @hilo applicaties .anni s, isst. Ns.cerner 6 Claims.

This invention relates to bending pipe, tubn ing, solid bars, wire andthe like; more particu-- lai-ly to bending such articles to straight;and still more particularly to straightening lengths oi such articleswhich, without abrupt bends anywhere, depart somewhat as a whole from aright line. rlhe invention includes both a method and an apparatus.

The invention is intended for metal pipe and tubin.Cr especially, but isapplicable also to bars, wire and other articles of the saine generalkind, as above indicated. For brevity, the terms articles and elongatedarticles" are employed hereinaiter to indicate all articles oi thislrind.

According to the method of the invention, each and every short length,and preferably each and every iniinitesimally short length, bi thearticle to be treated, is bent systematically in substantially or quiteevery direction, one of the bends (it may be the first one, so iar asfinal result is concerned) being made, preferably, at least on such ashort radius that the elastic limit oi the metal is exceeded (so thatthe length would have a permanent set were nothing further done with it)and the remaining bends being made on radii of various greater lengths,usually of successively greater lengths, until the iinal desired form,say the straight, is reached. From another aspeet, the method of theinvention consists of bending each short or elemental length of articleor article wall spirally, as itmay be called, in the` manner hereinafterdescribed. l

Basically the apparatus of the invention may consist or any piece,structure or apparatus providing an elongated smoothly-curving curvedguideway or path of various lengths of radii of curvature, the shortestof which exceeds, at least preferably, the elastic limit of the articleto be treated, and which path terminates and blends into, say, astraight exit portion, through which the elongated article can be passedwhile being rotated, and which piece or structure constrains the articleagainst local bending except on such radii as are prescribed by themethod of the lnvention. Preferably mechanism for pushing the elongatedarticles through the guideway or path is provided at the entrance end ofthe piece, structure or apparatus, and another mechanism to pull thearticle through the guideway or path is provided at the exit end of theguide-way providing piece, structure or apparatus, these mechanlsms alsoserving to rotate the article in passing.

These and other features of the invention appear in the accompanyingdrawing and the following description of the matters there illustrated.

in this drawing, Fig. l is a plan view, partly in section, ci? a machineembodying the invention. Fig. 2 is an end elevation, partly in section,of the article-pushing mechanism, and also 0i' the article-pullingmechanism, oi Fig. l. Fig. 60 3 is a side elevation o one of thosemechanisms. Fig. i is an illustrative diagram referred to hereinafter.

While the method or the invention is not limitd ed to any particularapparatus, this method may be understood from the apparatus illustratedin the drawing which I have devised for carrying it out. The elongatedcurved guideway or path for the article is outlined by a metal helix l',the turns of which are placed substantially as close together aspossible. internally, the diam= eter of the helix is only a littlegreater than the external diameter of the article, say A 17, to betreated. Such a hellxis a preferred device for outlining the guideway orpath, since it bears t5 on the article at many closely-spaced points andthus is well adapted to prevent bending or the article anywhere on aradius other than the re4 spective local radius of curvature of theguideway. To hold the helix in the desired shape for the path, the helixmay rest against a base plate 2, b e provided at its sides with twoexible plates 3 placed at right angles to the base-plate 2, and. be helddown to the baseplate by a cover plate d placed parallel with thebaseplate 2. The two plates 2' and i may be permanently placed withrespect to each other. Preferably however the side plates 3 are heldbetween a series of thread ed bolts `5, 6, 7, 8, 9, 10 and l1, whichare. provided in such numbers as may be necessary to confine wtheseplates and the helix to the desired curved path and which may be mountedin bracl= ets l2 permanently fastened between the lower and upper plates2 and fl; by means of the bolts the curvature of the path may beadjusted from time to time, for example to suit the particular metal ofthe articles used with it. To set up the machine for say the length oftubing l'l, I first take a short piece of this tubing or a piece of jsimilar tubing made from the same metal, and lull) by bending thepleceon successively shorter radii of curvature, I 'lnd the radius orcurvature, or, say, about the longest radius of curvature, which, whenthe tubing is bent on it, gives the piece a permanent set. That is tosay, I first find a radius of curvature, and usually about the longestradius of curvature,'whlch exceeds the elastic limit of the article tobe treated. I then so set the threaded bolts, say 5 and 6, as to curvethis end of the lhelix 1 to this radius which exllo `stantiallytangentially into, its straight portion l through, as may be found bytrial. The direc- ;with reference to Fig. 4 differs from the opera-'.whole these parts are stationary and the tube 17 vthis short length istreated as held against ro- .bending of the short length and the effecton it.

by the relative sharpness of the angle 18, 19, 20.

2 masones ceeds the elastic limit of the article 17. It being This isthe first or a preliminary step in the opdesired to straighten this tube17 for example, erations. vNext, one end of the length or elethat is tosay, the tube being somewhat bent it ment, say the end 18-19, is movedabout, relabeing desired to straighten it accurately, the tive to theother end 19-20, in the manner illusthreaded bolts at the opposite endof the helix, say trated in the diagrammatic figure; that is to say, 10and 11, are so set as to bring the axis of relative to 20 the end 18 isforced to travel along this portion of the helix 11 into a straight or aspiral, as from point 18 to point 22,` to 23, to 24, right line for atleast a short distance. The inand so on until the finish point 37 isreached, the termediate bolts, say 7, 8 and 9, are then so adlatterbeing, in the present instance, the center justed as to cause the axisof the helix to folof the spiral, and in the center line of the part lowa smooth curve from the entrance end of 19-20 extended representing thatthe element short radius of curvature to, and to blend sub- 18-19-20, atthe conclusion of the operations on it, is straight. Each and everyinfinitesimally short length of the tube being bent in exactly the samemanner, it is evident that the tube as a whole will have a uniformlengthwise shape at the iinish of the operation. In effect, everyinfinitesimally short length of tube passed through the device of Fig. 1is bent in this manner and this systematic bending is the preferredmethod of the invention.

The mechanisms illustrated at the lower left of Fig. l and outlined atthe upper right, are mechanisms for pushing and pulling the articlesthrough the guideway or path 1, and simultaneously rotating them. Thedescription of one will serve as a description of the other also, thetwo beingalike. In flxed spaced brackets 43 and 44 are -journaled twoannular. heads 45 and 46 which, in conjunction with the parallel bars47, 48, 49.and 50 Joining the heads, constitute a rotating frame. Theexternal periphery of head 46 is toothed for driving by a gear 51 onshaft 52, which may be driven, for example, by an electric motor 53directly, or through an extension of the shaft and universal Joints 54'in the manner of lthe puller mechanism at the upper right of Fig. 1. Thebars 47 and 48 carry a pair of belt sprockets 55 and likewise the bars49 and 50 carry a pair of belt sprockets 58; each pair of sprocketscarries a chain belt 57 or 58 to which are attached article (tube)grippers 59 suitably recessed to grab the article, e. g. the tube 17. Aninternal gear 63 is fixed to one of the brackets. Shafts 64 and 65carried by the frame heads 45 and 46, are provided with gears 67 and 68respectively, meshing with internal gear 63 for driving thereby as theframe is rotated; through their miter gears 69 and 70 and the mitergears 71 and 72 on shafts of sprockets 55 and 56 these 125 shafts 64 and65 drive the sprockets 55 and 56 and thereby the belts 57. It will beobserved therefore that the motor 53 will rotate the frames of the tubepushing mechanism (at the lower left of Fig. 1) and the tube pullingmechanism (at the upper right) and thereby the tube, and simultaneously,the motor driving in the proper direction, ywill rotate the sprockets 55and 56 in the various directions indicated'by the arrows on thesprockets and thereby cause the two mechanisms to simultaneously pushand pull the tube through the guideway in the direction indicated by thearrow adjacent the tube.

It will be understood however that ,the invention is not limited to thedetails illustrated and 140 dlescribed, except as appears hereinafter inthe c aims.

in ,other words, I so adjust the intermediate bolts that the radii ofcurvature of the curved portion of the helix axis increase gradually andsuccessively from the bolts 5 or 6 to about the bolts 11, or perhaps toa point somewhat farther back toward the bolts 10, and at this pointcause the helix axis to blend tangentially into its straight part.Preferably the curve of the curved portion of the path is a parabola. Tostraighten then say the tubes 17. it is only necessary to force the tubethrough the path of guideway provided by thehelix 1 and simultaneouslyrotate the tube a suitable number of times as it passes tion ofrotation, that` is to say whether clockwise or counter-clock-wise,isimmaterial; however it seems to be somewhat easier to force a tube 17through the pathway when rotating' it in a direction contrary to thescrew-thread-efiect provided by the turns ofO the helix. The path may belubricated as desired or found necessary.

It will be observed that passing a' tube 17 through such a path whilerotating the tube, causes each and every infinitesirnally` short lengthor element of the tube to be bent repeatedly and systematically in everydirection, the bend near the entrance, near the bolts 5, being made onsuch a short radius of curvature that the'elastic limit of the metal isexceeded, and the remaining bends being made on radii of successivelygreater lengths until the straight portion of the path is reached nearits exit. Fig. 4 represents diagrammatically the treatment `which eachand every such short length undergoes in passingthrough such a guidewayas 1 while being rotated. In one respectV the operation described tiondescribed with reference to Fig. 1. Ilhat is to say, in Fig. 41 theguideway or path-providing parts mounted on the base plate 2 neitherrotate as a whole nor move longitudinally, but as a is moved through theguideway and at the same time is rotated within it; in Fig. 4, to thecontrary, in which only an inflnitesimally short length (18-19--20) of awhole tube is shown,

tation and longitudinal movement while, as it were, the guideway isassumed to be passed over this short length of tube and at the same timerotated about this short length. The actual is the same in both cases.Assuming (what is probably not the fact) that the bend-A ing of eachelement is concentrated at one I claim:

point 19 in it, then the line 18, 19, 20 may be 1. Apparatus for bendingelongated'articles,4 taken as representing an inilnitesimally ab@comprising means providing an elongated curved length or longitudinalelement of the wall of the rpath for the article and bearing on thearticle at tube, while occupying, say, a position about oppo' suchclosely spaced points thereon as to confine site the bolts 5. The'element is here bent on a the article to such smoothly-curving pathwithout short radius of curvature, as represented in Fig. 4 permittinglocal bending of the article on a radius materially shorter than therespective local raassess@ l dius of curvature of the path, the radiusci curvature of said path at one point exceeding the elastic limit ofthe article and the radii of curvature of said curved path at one sideof said point being of greater lengths and of lengths successivelygreater than each other, and mechanism for pushing an elongated articlethrough said means, in the direction of from said point of radiusexceeding the elastic limit to the portion of the cui ve of longerradii, and for simultaneously rotating the article within said means.

2. Apparatus for bending elongated articles, comprising means providingan elongated curved path for the article and bearing on the article atsuch closely spaced points thereon as to confine the article to suchsmoothly-curving path without permitting local bending of the article ona radius materially shorter than the respective local radius ofcurvature of the path, the radius o! curvature of said path. at onepoint exceeding the elastic limit of the article and the radii ofcurvature of said curved path a't one side of said point being ofgreater lengths and of lengths successively greater than each other, andmechanism for pulling an elongated article through said means, in thedirection of from said point o! radius exceeding the elastic limit tothe portion of the curve of longer radii, and for simultaneouslyrotating the article within said means.

3. Apparatus for bending elongated articles, comprising means providingan elongated curved path for the article and bearing on the article atsuch closely spaced points thereon as to corinne the article to suchsmoothly-curving path without permitting local bending of the article ona article.

radius materially shorter than the respective local radius oi curvature(1f/the path, the radius of curvature oi said path at one pointexceeding the elastic limit of the article and the radii of curvature ofsaid curved path at one side oi'. said point being of greater lengthsand of lengths succcssively greater than each other, and mechanism forpulling and mechanism for pushing an elongated article through saidmeans, in the direction of from said point of radius exceeding theelastic limit to the portion of the curve of longer radii, and forsimultaneously rotating the article within said means.

4. The method of treating articles oi the kind described for thepurposes described, which consists in bending each short length of thearticle on a radius exceeding the elastic limit of the article andthereafter repeatedly bending the same short length of the article invarious directions to successively lesser degrees. 5. The method ofstraightening an elongated article, which consists in bending eachsubstantially-lnnitesimally short length of the article on a. radiusexceeding the elastic limit of the article and thereafter repeatedlybending the same in various directions to successively lesser -degreesuntil the vstraight condition is reached.

6. Apparatus for bending elongated articles, comprising means forconning the article to a substantially parabolic path and means forcausing relative rotational and longitudinal movement between saidconfining means and the elongated JOHN F. LAWSON.

will

